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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef _LINUX_HIGHMEM_H |
3 | #define _LINUX_HIGHMEM_H | |
4 | ||
1da177e4 | 5 | #include <linux/fs.h> |
597781f3 | 6 | #include <linux/kernel.h> |
187f1882 | 7 | #include <linux/bug.h> |
1da177e4 | 8 | #include <linux/mm.h> |
ad76fb6b | 9 | #include <linux/uaccess.h> |
43b3a0c7 | 10 | #include <linux/hardirq.h> |
1da177e4 LT |
11 | |
12 | #include <asm/cacheflush.h> | |
13 | ||
13f876ba | 14 | #include "highmem-internal.h" |
03beb076 | 15 | |
13f876ba TG |
16 | /** |
17 | * kmap - Map a page for long term usage | |
18 | * @page: Pointer to the page to be mapped | |
19 | * | |
20 | * Returns: The virtual address of the mapping | |
21 | * | |
22 | * Can only be invoked from preemptible task context because on 32bit | |
23 | * systems with CONFIG_HIGHMEM enabled this function might sleep. | |
24 | * | |
25 | * For systems with CONFIG_HIGHMEM=n and for pages in the low memory area | |
26 | * this returns the virtual address of the direct kernel mapping. | |
27 | * | |
28 | * The returned virtual address is globally visible and valid up to the | |
29 | * point where it is unmapped via kunmap(). The pointer can be handed to | |
30 | * other contexts. | |
31 | * | |
32 | * For highmem pages on 32bit systems this can be slow as the mapping space | |
33 | * is limited and protected by a global lock. In case that there is no | |
34 | * mapping slot available the function blocks until a slot is released via | |
35 | * kunmap(). | |
298fa1ad | 36 | */ |
13f876ba | 37 | static inline void *kmap(struct page *page); |
525aaf9b | 38 | |
13f876ba TG |
39 | /** |
40 | * kunmap - Unmap the virtual address mapped by kmap() | |
41 | * @addr: Virtual address to be unmapped | |
42 | * | |
43 | * Counterpart to kmap(). A NOOP for CONFIG_HIGHMEM=n and for mappings of | |
44 | * pages in the low memory area. | |
78b6d91e | 45 | */ |
13f876ba | 46 | static inline void kunmap(struct page *page); |
298fa1ad | 47 | |
13f876ba TG |
48 | /** |
49 | * kmap_to_page - Get the page for a kmap'ed address | |
50 | * @addr: The address to look up | |
51 | * | |
52 | * Returns: The page which is mapped to @addr. | |
53 | */ | |
54 | static inline struct page *kmap_to_page(void *addr); | |
1da177e4 | 55 | |
13f876ba TG |
56 | /** |
57 | * kmap_flush_unused - Flush all unused kmap mappings in order to | |
58 | * remove stray mappings | |
59 | */ | |
60 | static inline void kmap_flush_unused(void); | |
1da177e4 | 61 | |
13f876ba | 62 | /** |
f3ba3c71 | 63 | * kmap_local_page - Map a page for temporary usage |
13f876ba TG |
64 | * @page: Pointer to the page to be mapped |
65 | * | |
66 | * Returns: The virtual address of the mapping | |
67 | * | |
13f876ba TG |
68 | * Can be invoked from any context. |
69 | * | |
70 | * Requires careful handling when nesting multiple mappings because the map | |
71 | * management is stack based. The unmap has to be in the reverse order of | |
72 | * the map operation: | |
73 | * | |
f3ba3c71 TG |
74 | * addr1 = kmap_local_page(page1); |
75 | * addr2 = kmap_local_page(page2); | |
13f876ba | 76 | * ... |
f3ba3c71 TG |
77 | * kunmap_local(addr2); |
78 | * kunmap_local(addr1); | |
13f876ba TG |
79 | * |
80 | * Unmapping addr1 before addr2 is invalid and causes malfunction. | |
81 | * | |
82 | * Contrary to kmap() mappings the mapping is only valid in the context of | |
83 | * the caller and cannot be handed to other contexts. | |
84 | * | |
85 | * On CONFIG_HIGHMEM=n kernels and for low memory pages this returns the | |
86 | * virtual address of the direct mapping. Only real highmem pages are | |
87 | * temporarily mapped. | |
88 | * | |
f3ba3c71 TG |
89 | * While it is significantly faster than kmap() for the higmem case it |
90 | * comes with restrictions about the pointer validity. Only use when really | |
91 | * necessary. | |
92 | * | |
93 | * On HIGHMEM enabled systems mapping a highmem page has the side effect of | |
94 | * disabling migration in order to keep the virtual address stable across | |
95 | * preemption. No caller of kmap_local_page() can rely on this side effect. | |
96 | */ | |
97 | static inline void *kmap_local_page(struct page *page); | |
98 | ||
99 | /** | |
100 | * kmap_atomic - Atomically map a page for temporary usage - Deprecated! | |
101 | * @page: Pointer to the page to be mapped | |
102 | * | |
103 | * Returns: The virtual address of the mapping | |
104 | * | |
105 | * Effectively a wrapper around kmap_local_page() which disables pagefaults | |
106 | * and preemption. | |
107 | * | |
108 | * Do not use in new code. Use kmap_local_page() instead. | |
13f876ba TG |
109 | */ |
110 | static inline void *kmap_atomic(struct page *page); | |
5a178119 | 111 | |
13f876ba TG |
112 | /** |
113 | * kunmap_atomic - Unmap the virtual address mapped by kmap_atomic() | |
114 | * @addr: Virtual address to be unmapped | |
115 | * | |
116 | * Counterpart to kmap_atomic(). | |
117 | * | |
f3ba3c71 TG |
118 | * Effectively a wrapper around kunmap_local() which additionally undoes |
119 | * the side effects of kmap_atomic(), i.e. reenabling pagefaults and | |
13f876ba | 120 | * preemption. |
13f876ba | 121 | */ |
c1f60a5a | 122 | |
13f876ba TG |
123 | /* Highmem related interfaces for management code */ |
124 | static inline unsigned int nr_free_highpages(void); | |
125 | static inline unsigned long totalhigh_pages(void); | |
1da177e4 | 126 | |
13f876ba TG |
127 | #ifndef ARCH_HAS_FLUSH_ANON_PAGE |
128 | static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr) | |
e23c4597 IW |
129 | { |
130 | } | |
7438f363 | 131 | #endif |
1da177e4 | 132 | |
13f876ba TG |
133 | #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE |
134 | static inline void flush_kernel_dcache_page(struct page *page) | |
254f9c5c | 135 | { |
254f9c5c | 136 | } |
13f876ba | 137 | static inline void flush_kernel_vmap_range(void *vaddr, int size) |
298fa1ad | 138 | { |
298fa1ad | 139 | } |
13f876ba | 140 | static inline void invalidate_kernel_vmap_range(void *vaddr, int size) |
298fa1ad | 141 | { |
298fa1ad | 142 | } |
7438f363 | 143 | #endif |
980c19e3 | 144 | |
1da177e4 | 145 | /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */ |
487ff320 | 146 | #ifndef clear_user_highpage |
1da177e4 LT |
147 | static inline void clear_user_highpage(struct page *page, unsigned long vaddr) |
148 | { | |
1ec9c5dd | 149 | void *addr = kmap_atomic(page); |
1da177e4 | 150 | clear_user_page(addr, vaddr, page); |
1ec9c5dd | 151 | kunmap_atomic(addr); |
1da177e4 | 152 | } |
487ff320 | 153 | #endif |
1da177e4 LT |
154 | |
155 | #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE | |
769848c0 MG |
156 | /** |
157 | * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags | |
158 | * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE | |
159 | * @vma: The VMA the page is to be allocated for | |
160 | * @vaddr: The virtual address the page will be inserted into | |
161 | * | |
162 | * This function will allocate a page for a VMA but the caller is expected | |
163 | * to specify via movableflags whether the page will be movable in the | |
164 | * future or not | |
165 | * | |
166 | * An architecture may override this function by defining | |
167 | * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own | |
168 | * implementation. | |
169 | */ | |
1da177e4 | 170 | static inline struct page * |
769848c0 MG |
171 | __alloc_zeroed_user_highpage(gfp_t movableflags, |
172 | struct vm_area_struct *vma, | |
173 | unsigned long vaddr) | |
1da177e4 | 174 | { |
769848c0 MG |
175 | struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags, |
176 | vma, vaddr); | |
1da177e4 LT |
177 | |
178 | if (page) | |
179 | clear_user_highpage(page, vaddr); | |
180 | ||
181 | return page; | |
182 | } | |
183 | #endif | |
184 | ||
769848c0 MG |
185 | /** |
186 | * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move | |
187 | * @vma: The VMA the page is to be allocated for | |
188 | * @vaddr: The virtual address the page will be inserted into | |
189 | * | |
190 | * This function will allocate a page for a VMA that the caller knows will | |
191 | * be able to migrate in the future using move_pages() or reclaimed | |
192 | */ | |
193 | static inline struct page * | |
194 | alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma, | |
195 | unsigned long vaddr) | |
196 | { | |
197 | return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr); | |
198 | } | |
199 | ||
1da177e4 LT |
200 | static inline void clear_highpage(struct page *page) |
201 | { | |
1ec9c5dd | 202 | void *kaddr = kmap_atomic(page); |
1da177e4 | 203 | clear_page(kaddr); |
1ec9c5dd | 204 | kunmap_atomic(kaddr); |
1da177e4 LT |
205 | } |
206 | ||
0060ef3b MWO |
207 | /* |
208 | * If we pass in a base or tail page, we can zero up to PAGE_SIZE. | |
209 | * If we pass in a head page, we can zero up to the size of the compound page. | |
210 | */ | |
211 | #if defined(CONFIG_HIGHMEM) && defined(CONFIG_TRANSPARENT_HUGEPAGE) | |
212 | void zero_user_segments(struct page *page, unsigned start1, unsigned end1, | |
213 | unsigned start2, unsigned end2); | |
214 | #else /* !HIGHMEM || !TRANSPARENT_HUGEPAGE */ | |
eebd2aa3 | 215 | static inline void zero_user_segments(struct page *page, |
0060ef3b MWO |
216 | unsigned start1, unsigned end1, |
217 | unsigned start2, unsigned end2) | |
eebd2aa3 | 218 | { |
1ec9c5dd | 219 | void *kaddr = kmap_atomic(page); |
0060ef3b | 220 | unsigned int i; |
eebd2aa3 | 221 | |
0060ef3b | 222 | BUG_ON(end1 > page_size(page) || end2 > page_size(page)); |
eebd2aa3 CL |
223 | |
224 | if (end1 > start1) | |
225 | memset(kaddr + start1, 0, end1 - start1); | |
226 | ||
227 | if (end2 > start2) | |
228 | memset(kaddr + start2, 0, end2 - start2); | |
229 | ||
1ec9c5dd | 230 | kunmap_atomic(kaddr); |
0060ef3b MWO |
231 | for (i = 0; i < compound_nr(page); i++) |
232 | flush_dcache_page(page + i); | |
eebd2aa3 | 233 | } |
0060ef3b | 234 | #endif /* !HIGHMEM || !TRANSPARENT_HUGEPAGE */ |
eebd2aa3 CL |
235 | |
236 | static inline void zero_user_segment(struct page *page, | |
237 | unsigned start, unsigned end) | |
238 | { | |
239 | zero_user_segments(page, start, end, 0, 0); | |
240 | } | |
241 | ||
242 | static inline void zero_user(struct page *page, | |
243 | unsigned start, unsigned size) | |
244 | { | |
245 | zero_user_segments(page, start, start + size, 0, 0); | |
246 | } | |
01f2705d | 247 | |
77fff4ae AN |
248 | #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE |
249 | ||
9de455b2 AN |
250 | static inline void copy_user_highpage(struct page *to, struct page *from, |
251 | unsigned long vaddr, struct vm_area_struct *vma) | |
1da177e4 LT |
252 | { |
253 | char *vfrom, *vto; | |
254 | ||
1ec9c5dd CW |
255 | vfrom = kmap_atomic(from); |
256 | vto = kmap_atomic(to); | |
1da177e4 | 257 | copy_user_page(vto, vfrom, vaddr, to); |
1ec9c5dd CW |
258 | kunmap_atomic(vto); |
259 | kunmap_atomic(vfrom); | |
1da177e4 LT |
260 | } |
261 | ||
77fff4ae AN |
262 | #endif |
263 | ||
a4602b62 KA |
264 | #ifndef __HAVE_ARCH_COPY_HIGHPAGE |
265 | ||
1da177e4 LT |
266 | static inline void copy_highpage(struct page *to, struct page *from) |
267 | { | |
268 | char *vfrom, *vto; | |
269 | ||
1ec9c5dd CW |
270 | vfrom = kmap_atomic(from); |
271 | vto = kmap_atomic(to); | |
1da177e4 | 272 | copy_page(vto, vfrom); |
1ec9c5dd CW |
273 | kunmap_atomic(vto); |
274 | kunmap_atomic(vfrom); | |
1da177e4 LT |
275 | } |
276 | ||
a4602b62 KA |
277 | #endif |
278 | ||
6a0996db IW |
279 | static inline void memcpy_page(struct page *dst_page, size_t dst_off, |
280 | struct page *src_page, size_t src_off, | |
281 | size_t len) | |
282 | { | |
283 | char *dst = kmap_local_page(dst_page); | |
284 | char *src = kmap_local_page(src_page); | |
285 | ||
ca18f6ea | 286 | VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE); |
6a0996db IW |
287 | memcpy(dst + dst_off, src + src_off, len); |
288 | kunmap_local(src); | |
289 | kunmap_local(dst); | |
290 | } | |
291 | ||
292 | static inline void memmove_page(struct page *dst_page, size_t dst_off, | |
293 | struct page *src_page, size_t src_off, | |
294 | size_t len) | |
295 | { | |
296 | char *dst = kmap_local_page(dst_page); | |
297 | char *src = kmap_local_page(src_page); | |
298 | ||
ca18f6ea | 299 | VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE); |
6a0996db IW |
300 | memmove(dst + dst_off, src + src_off, len); |
301 | kunmap_local(src); | |
302 | kunmap_local(dst); | |
303 | } | |
304 | ||
305 | static inline void memset_page(struct page *page, size_t offset, int val, | |
306 | size_t len) | |
307 | { | |
308 | char *addr = kmap_local_page(page); | |
309 | ||
ca18f6ea | 310 | VM_BUG_ON(offset + len > PAGE_SIZE); |
6a0996db IW |
311 | memset(addr + offset, val, len); |
312 | kunmap_local(addr); | |
313 | } | |
314 | ||
bb90d4bc IW |
315 | static inline void memcpy_from_page(char *to, struct page *page, |
316 | size_t offset, size_t len) | |
317 | { | |
61b205f5 | 318 | char *from = kmap_local_page(page); |
bb90d4bc | 319 | |
ca18f6ea | 320 | VM_BUG_ON(offset + len > PAGE_SIZE); |
bb90d4bc | 321 | memcpy(to, from + offset, len); |
61b205f5 | 322 | kunmap_local(from); |
bb90d4bc IW |
323 | } |
324 | ||
325 | static inline void memcpy_to_page(struct page *page, size_t offset, | |
326 | const char *from, size_t len) | |
327 | { | |
61b205f5 | 328 | char *to = kmap_local_page(page); |
bb90d4bc | 329 | |
ca18f6ea | 330 | VM_BUG_ON(offset + len > PAGE_SIZE); |
bb90d4bc | 331 | memcpy(to + offset, from, len); |
61b205f5 | 332 | kunmap_local(to); |
bb90d4bc IW |
333 | } |
334 | ||
28961998 IW |
335 | static inline void memzero_page(struct page *page, size_t offset, size_t len) |
336 | { | |
337 | char *addr = kmap_atomic(page); | |
338 | memset(addr + offset, 0, len); | |
339 | kunmap_atomic(addr); | |
340 | } | |
341 | ||
1da177e4 | 342 | #endif /* _LINUX_HIGHMEM_H */ |